>> Rafael, thanks for the clarification in the other mail.>>>> Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>>>>> I think we need to get this into 3.2-stable as well, as Jiri mentioned.> > Yes, we do.> > Below it goes again with the missing comment in user.c and a changelog.> > Please let me know if there's anything wrong with it, otherwise I'm going> to push it to Linus in a couple of days.> > Thanks,> Rafael> > ---> From: Rafael J. Wysocki <rjw@sisk.pl>> Subject: PM / Hibernate: Fix s2disk regression related to freezing workqueues> > Commit 2aede851ddf08666f68ffc17be446420e9d2a056> > PM / Hibernate: Freeze kernel threads after preallocating memory> > introduced a mechanism by which kernel threads were frozen after> the preallocation of hibernate image memory to avoid problems with> frozen kernel threads not responding to memory freeing requests.> However, it overlooked the s2disk code path in which the> SNAPSHOT_CREATE_IMAGE ioctl was run directly after SNAPSHOT_FREE,> which caused freeze_workqueues_begin() to BUG(), because it saw> that worqueues had been already frozen.> > Although in principle this issue might be addressed by removing> the relevant BUG_ON() from freeze_workqueues_begin(), that would> reintroduce the very problem that commit 2aede851ddf08666f68ffc17be4> attempted to avoid into that particular code path. For this reason,> to fix the issue at hand, introduce thaw_kernel_threads() and make> the SNAPSHOT_FREE ioctl execute it.> > Special thanks to Srivatsa S. Bhat for detailed analysis of the> problem.> > Reported-and-tested-by: Jiri Slaby <jslaby@suse.cz>> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>> Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>